Clam-shell bucket



Feb. 25, 1930.

P. T. ROBIN GLAM SHELL BUCKET Filed May 16 1928 2 Sheets-Sheet l Feb. 25, 1930. P, T, ROBIN 1,748,586

CLAM SHELL BUCKET Filed May 16. 1928 2 Sheets-Sheet 2 WW Wma Patented Feb. 2s, 1930 PATENT 1.01. F CE -i 2mn a'. nonna, or mxnwoom onro,

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COLUMBUS, OHIO,

ASSIGNOR, .BY VINIESNE ASSIGNMENTS, TO

A. CORPORATION `OIB OHIO cnam-snm :wcm

l f Applicatie; 'mea my 1e, 192s; serm No. 218,294.

This invention v` relates to graby buckets of the t e which are commonlyknown as clamshell uckets, and which are operated by means of closing and supporting cables or 5 chains.

One of the objects of the invention is to provide a clam-shell bucket having a relatively great spread or length between the cutting jaws when in open position, but at j the same time maintaining the bucket of normal hei ht and with its spreading parts so arrangexgi as to develop ample cuttlng and closing power stroke.

It is well recognized that the ability of a clam-shell bucket to gather` a load, other factors being equal, increases directly with the increase of spread or length between the cutting jaws when the jaws are in open position and in engagement with the material to be handled.

In the conventional types of single hinge buckets which are at present in use, the opening of the jaws is, practically speaking, re-

.5 stricted and any attempt to increase the spread of the jaws to a complete or full open position, or, in other words, to as complete an opening as is possible with the bucket of the present invention, results in a considerable I0 reduction in the` available power for forcing the jaws through the material, particularly during the latter part of the closing movement of the shells of the bucket, unless erchance a desired result may be obtaine by l materially increasing the height of the bucket.

As before stated, the object of the present inventionis to overcomethe defects inherent in the usual type of single hinged buckets, by

l0 means andA mechanism whichare clearly described and set forth' in the accompanying specication.

ReiereriiceshOuhi be. had torttlethaccomanymg rawln ormm a a o es ec- 1cation, in whi, v g p p toward the end of its closing Figurey 1 is a side elevation ofthe bucket in closed position.

` Figure 2 is-anend view of the bucket partially in section and partially in elevation.

F1gure 3 is a side elevation showing the bucket in full open position.

Figure 4: is an end elevation of the bucket 1n open osition.

The s ells or scoops of the buckets are represented respectively at l and 2, these being o the usual form and require no extended description. The usual cutting jaws 3 are employed in connection with the shells or scoops. The bell crank lever 4 is at one end pivotally connected upon one of the scoops y means of a transversely extending pin 6. This member 4 is also mounted so as to be capable of independently turning with respect t0 the pin 6, upon' a transversely eX- tending shaft 5. At the extreme or free end of the member 4 there is supported a sheave 6, which,'in cooperation with a sheave? carried upon the head piece 8, receives an operating cable or chain 9 which at one end, as indicated at 10,.is fixed upon the head 8 and is reeved upon the sheaves 63L and 7 passing from the sheave 7 Vin a vertical direction, as indicated by the part marked 9*.

The supporting rope for the bucket is indicated at 11, and is fastened in the head 8 in any desired manner.

Arms 12 and 12ll are pivotally mounted at the ends of the shaft 5, and the opposite ends of these arms are pivotally connected to the opposite sides of the scoop 2.

In order to limit the outward swing of the scoops or buckets 1 and 2, a retaining member in the form of a chain 13 is employed, one end of the chain being secured to the headz as indicated at 13, and the opposite end being secured to the member 4, as indicated at 15.

VThe shell or bucket 2 is supported fromY the head 8 by means of a pair of arms 16, these arms being pivotally connected at one end. to the head 8 and at their opposite l0 with the head 8 by means of gusset plates,

one of which is indicated at 18.

' Two pairs of toggle arms 19 and 20 are pivotally connected at one of their ends with the shaft 5 and at their opposite ends are pivotally mounted upon the arms 16 and 17 at points above 4the point of pivotal connection of the arms 16 and 17 with their respective scoops 2 and 1.

A brace member 21 and set collars, one of which is indicated at 22, are provided to resist any inward movement of the toggle arms 19 and 20.

The operation of the bucket is as follows:

Assuming that the bucket is in closed osition and that the bucket is supporte by eans of the cable 9, the first requirement is t at the support for the bucket be transferred to the cable 11, and that the cable 9 be slacked. Upon this being done it is evident that the weight of the lever member 4, shaft 5 and the parts associated therewith, will exert a downward pull upon the toggle members 19- and 20, causing the toggle arms to straighten and simultaneously spreadingapart the lower ends of the bail arms 16v and 17. The combined movement of the scoops 1 and 2, under the action of theforces which have above been described, causes the scoops to move into the position shown in Figure 3, and by employing a suitable length for the stop chain 12 the opening.

` of the jaws may be arrested at any predetermined position or limit of spread.

In the open position the bucket is then lowered by the cable 11 until the jaws of the bucket rest upon the material which is to be handled.

In order to close the bucket the cable 11 is relaxed and a lifting force applied to the cable 9. This cable through the sheave arrangement 6 and 7 will multiply the lifting power exerted and apply it directly at the end of the member 4. The upward movement of the sheave 6 will obviously cause the member 4 to move about its pivotal connections, thereby eecting a movement of the scoop 1, while the members 12 and 12a. whichare pivotally connected with the shaft 5 and the scoop 2 will likewise cause a movement of the scoop 2. j

The. upward movement of the shaft 5 moves the toggle members 19 and 20 from the position shown in Figure 3 to the position shown in Figure 1.

If the bucket is to penetrate and gather up material satisfactorily, resistance to the lifting force must be less than the total weight of the bucket and of the quality of material gathered into the scoops of the bucket at any given stage. Also the multiplication of the lifting force through the cable 9 and thevarious internal leverages of the bucket, must be such that with the lifting force the tendency of the jaws to move toward one an- Y other throu h the material, will exceed the resistance o the material which is Abetween ly at a right angle to the direction of the force applied vto it by means of the closing cable 9, so that the greatest possible upward pull will be exerted on the central shaft 5.

The second factor consists in the factthat the toggle action of the links 19 and 20 which, upon application of the upward pull of the shaft 5, tends to draw the lower ends of. the bail arms 16 and 17 together, which action is then transmitted to the scoops 1 and 2.

Referring to Figure 1, it will be appreciated from the foregoing description that the greater the included angle between the links 19 and 20 the more effective will be their action in augmenting both the opening and closing functions of the bucket when the scoops are at or near the closed position.

It will be noted that the lposition of the sheaves 7 with respect to the upwardly extending portion of the cable 9 when supporting the bucket will cause the same to assume a position substantially upon the vertical axis of the bucket, hence the bucket will remain in a vertical position while suspended by the cable 9, thus avoiding any undue spilling of material over the backs of the scoops. With this positioningof the sheave 7 it follows that in order toobtain the right, angle pull upon the upper axis of the member 4, the sheave 6 must be positioned well over to one side of the bucket. Y

Referring to Figure 3, it will be obvious that the toggle links 20 and 21 in combinationwith the other parts of the bucket mechanism, will cause the lever 4 to rotate with respect to the scoop 1 in such a manner that the sheaves 6 are prevented from extending below the base line to which the outer ends of the aws of the scoop are tangent, even when the ucket is in extreme open position.

From the foregoing description herein contained it will be seen that the bucket mechanism may be readily proportioned so as to provide for an excessively wide open spread of the jaws when the scoops vare in open position, and still retain ample closing' power,

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without increases either in the height of the bucket or in the number of parts required for the closing, and further the bucket w1l1 pos- .;sess unusual closing power in relation to its and Spread, and further the bucket 'movable bail arms connected at one end to the said head member and also pivotally connected at their opposite ends to the outer portions of the scoops, a transversely extending shaft, a hinge member mounted for turning about said shaft', one end of said hinge member being pivotally connected with inner portions of one of the scoops, a second hinge member pivotally connected with inner portions of the other of said scoops and also being ivotally mounted upon the said shaft, one ofp the aforesaid hinge members having a portion which extends beyond the aforesaid shaft, sheave means mounted upon the said extension and cooperating with sheave means carried by the head with a cable cooperating with the said sheave means, whereby the opening and closing movements of the scoops are controlled.

2. In a clam-shell bucket, the combination of a head member, a pair of scoops, relatively movable bail arms connected at one end to the said head member and at their opposite ends connected to the, outer portions of said scoops, hinge members pivotally connected to the inner portions of said scoops, a transverse shaft upon which the said hinge members are pivoted, toggle link members pivotally attached at one of their ends tothe said transverse shaft and at their opposite ends having pivotal connection with the said bail arms, and operating means for effecting the opening and closing movement of said scoops.

3. In a clam-shell bucket, the combination of a head member, a pair of scoops, relatively movable bail arms connected at one end to the said headfmember and at their op osito ends connected to the outer portions o said scoops hinge members which are respectively pivo'ta y connected to the adjacent inner portions of each of thevscoo s, av transverse ,o shaft-, upon which the said in e members are p1vota1lymounted,`one ofsaid gemembers being provided with an extension, a sheave carried by said extension, a sheave earned by the head member in general alignment with the first mentioned sheave member, a cable cooperating with said sheaves for effecting opening and closing movement of the sheaves, to gle links pivotally connected with the said s aft at one of their ends and pivotally connected with the bail arms at points adjacent the pivotal connection of said bail arms with the said scoops.

In testimony whereof, I hereunto afx my signature.

' PHILIP T. ROBIN. 

